This paper presents an study to improve the design of a valve spring for diesel engines. In order to get a guide line for design optimisation, as well as providing the better understanding of the mechanism, a dynamic model is first analysed. After considering the valve spring as a linear mechanical system, loads and dynamic stresses are hereby analysed. The study will be focusing natural frequencies and resonance condictions of the springs. Supporting the fatigue analysis a finite element study is performed using the NASTRAN 67 code and the I DEAS VI solid modeller.As a final result a single spring design is proposed to substitute the double spring concept. Eletronic devices used in test bench to cheek single spring ability of controlling the value train at high speed are also presented. It is also hereby presented validation procedures and test results to verify the theoretical predictions.